Topic 4: Drug testing

Question 1

Plants produce chemicals as a ______ ________ to ‘poison’ animals or micro-organisms

Humans can exploit these chemicals to produce medicines/drugs to kill pathogenic bacteria or cancer cells - used at doses which leaves the human _____.

Answer 1

defence mechanism

alive

Question 2

Key Summary: Describe William Withering’s/historic drug testing
(5 steps)

Answer 2

1. Drug extracted from plant
2. Drug tested on patients with disease
3. Side effects recorded
4. Larger group used to discover the most effective dose (slowly increased dose until patients experienced diarrhoea and vomiting, then reduced dose slightly – most effective dose)
5. Recorded all results meticulously and published results

Question 3

What 4 things do modern drug tests include?

Answer 3

Three-phased testing

Randomisation

Placebo

Double blind trial

Question 4

Explain clinical trial phase 1

3 points

Answer 4

1. Small group/100 people
2. Healthy humans (not patients)
3. Done for safety - side effects

Question 5

Explain clinical trial phase 2

4 points

Answer 5

1. Small group/100-300 people
2. Patients with the disease
3. To see if the drug works
4. To establish a safe dose

Question 6

Explain clinical trial phase 3

3 points

Answer 6

1. Large group/1000+ people
2. Patients with the disease
3. To monitor effectiveness/identify side effects in larger group
4. Randomisation creates two groups (one control group given a placebo/existing drug/other new drug)
5. Double-blind trial (doctor and patient do not know who is given new drug)
6. Use statistical analysis of data

Question 7

Key Summary: Describe how to carry out a modern drug test

6 steps

Answer 7

1. Extract compound from plant (name from question) and make drug (name from question)
2. Preclinical testing - test in vitro (human or animal cells/tissues in a petri dish) in laboratory OR test on animals OR both
3. Phase 1 – drug tested on healthy people (not patients!)
4. Review by independent scientists before allowing Phase 2
5. Phase 2 – drug tested on small groups of patients with the disease to determine effectiveness and optimum dose/concentration
6. Phase 3 - drug tested on larger groups of patients with the disease, double blind trial, two randomised groups where one given treatment and other a placebo or old drug, statistical test used to analyse results

Question 8

Key Summary: What are the similarities between William Withering’s/historic testing and modern testing?
(3 points)

Answer 8

1. Idea of extracting drug (from the plant)
2. Tested on patients.
3. Trying to find a suitable dose

Question 9

Key Summary: What are the differences between William Withering’s/historic testing and modern testing?
(8 points)

Answer 9

1. contemporary testing will use animals, Withering’s testing does not;
2. contemporary testing {tests on healthy people / has phase 1}, Withering’s tests on patients with disease;
3. contemporary testing pays volunteers, Withering’s does not ;
4. contemporary testing may involve double-blind trials, Withering’s testing does not ;
5. contemporary testing may use a placebo, Withering’s testing does not ;
6. contemporary testing {uses statistical analysis / phase 3 / large number (of people) } ;
7. contemporary testing has more regulation ;
8. contemporary testing controls other variables in tested cohort eg. age, lifestyle, Withering’s does not ;

Question 10

In modern drug testing, why do we test on animals? (3 points)

Answer 10

1. Tests for toxicity/adverse effects
2. No harm to humans
3. Less legal/ethical issues

Question 11

In modern drug testing, what are the ethical issues with testing on animals? (4 points)

Answer 11

1. depending on the animal it may feel pain/experience side-effects/die – animals have a right to life
2. animal cannot give consent
3. absolutist view – animals must never be used in drug tests
4. utilitarian view – benefits to humans may outweigh the risks to the animal

Question 12

In modern drug testing, why do is there random assignment/randomisation of patients?
(2 points)

Answer 12

1. to ensure the researchers do not influence results - remove bias
2. often 2 groups (control/placebo + treatment group) and patients are assigned at random to one group

Question 13

What is a double blind trial (1 point) and how is it performed (2 points)?

Answer 13

1. doctors and patients do not know who is on (new) drug or who is not
2. some people with (new) drug and some without (new) drug
3. Use placebo (e.g. sugar coated dummy pill)/old drug as a control for comparison to see if new drug works

Question 14

Why is a double blind trial important in a drug trial?

2 points

Answer 14

1. To see if new drug works better than placebo/old drug

2. reduces bias

Question 15

What is a placebo? (2 points)

Answer 15

1. Sugar-coated dummy pill (does not contain drug)

2. Control for comparison (if no existing drug)

Question 16

How is modern testing safer? (2 points)

Answer 16

1. Use of a specific active ingredient allows a precise dose to be given
2. Serious side effects are picked up during animal trials

Question 17

Modern drug testing have an improvement in reliability because… (4 points)

Answer 17

1. Larger sample size removes effects due to chance
2. Random assignment of patients removes bias in assigning them to a particular group
3. Double-blind testing removes bias from researcher
4. Statistical analysis of data helps distinguish effective drugs and doses